Pressure-resisting seal.



,l PATENTED APR. 2

D. GRAG. l PRESSURE RxgIsTINGNsEAL.

APPLICATION FILED OCT.

H0 MODEL.

UNiTnD STATS PATENT OFFICE.

DAVID CRAIG, OF MELROSE, MASSACHUSETTS.

PRESSURE-RESISTING SEAL.-

SPECIFICATION formingpa'rt of Letters Patent No. 725,937, dated April21,1903.

Application filed October 26, 1901. Serial No. 80,029. (No model.)`

To a/ZZ whom, it may concern:

Be it known that I, DAVID CRAIG, a citizen of the United States,residing at Melrose, in the county of Middlesex and State ofMassachusetts, have invented Vnew and useful Improvements inPressure-Resisting Seals, of which the following .is a specification.

My invention relates to pressure-resisting seals; and its object is toprovide a union or joint for coupling two pipes together which shallconstitute an absolute seal incapable of leakage withingiven pressures.A

A further object of my invention is to provide a plug or cap for closingthe end of a pipe which also shall constitute an absolutev seal.

A further object of my invention is to prosum of the Vertical heights ofthe ascending legs of said duct, provided the ascending passages-of theducts are filled with the liquid, while a column of air is sealed withineach of the descending passages of the ducts, or will maintain apressure equivalent to that exerted by such head of liquid.

My invention is illustrated in the accompanying drawings, in which-Figure I shows in vertical longitudinal section a pipe union or jointembodying my invention. Fig. 2 is a horizontal cross-section of Fig.- 1,taken through the line Fig. 3 is a vertical longitudinal section of apipe and plug or cap embodying my invention. Fig. 4 is a verticallongitudinal section of a pivotbearing embodying said invention, andFig. 5 is a side elevation of the pipe-union illustrated in Figs. 1 and2.

Like parts in all the iigures are indicated by the same letters ofreference.

Addressing my description first to the invention when employed as a pipeunion, joint, or coupling, as illustrated in Figs. l, 2, and 5, A is theupper member of the union and B the lower member. P and P representlengths of pipe to be joined together. One of these pipes, preferablythe pipe P of the upper member, is `'smaller than the other pipe and isadapted to telescope the latter when the union is elected. Said pipesare surrounded near their ends by collars C and C', respectively.Extending from the collars C and C' in the directions ot' the ends ofthe pipes are the seriesof concentric tubular walls D and Y D'.

In the lower member B these walls D' are preferably of equal height andof the same height as the end of the pipe P. In the upper member A thepipe P preferably extends a little beyond the endsof the walls D, as atP3, to assist in centering the two members of the union when they areplaced together. The collar C and tubular walls D and the correspondingparts C and D' in the lower member each form a series or nest ofconcentric cups of graded sizes, the walls of Athe cups of one memberbeing proportioned so as toL mesh with the hollows ot' the cups of theother member, as shown. Any suitable locking device, as thebayonet-joint J, may

lberemployed to secure the two members of It willbe seen that the theunion together. two series of nests of cups meshed with each other forma duct leading from the crevice or interstice or space between the pipesP l and P in ascending and descending convolutions. The height andnumber of these convolutions may be varied at pleasure, according to thepressure which the joint is intended to withstand, by varying the lengthand number of the tubular walls D and D. The seal formed by a liquidwithin the upward passages of these convolutions, a column of air beingconfined in the downward passages, will maintain a head of liquid inpipe P equivalent to the sums of the heights of the ascending passagesbetween the walls D and D'. Each of said members may be cast in onepiece, or the collars C and C and concentric walls D and D' may besoldered or fused on or otherwise secured, so as to render IOO 2 Y Yreses? i 's the pipe P to lead from a bowl and the pipe P to be thedrain-pipe supplied with a trap adapted to maintain the water at a givenheight in pipe P. Water is then admitted into the pipe P. When it risesto the height of the end of pipe P', it will trickle into the innermostcup between P and the inner of the tubular walls D. When the liquid inthis cup rises to the height of the lower end of thedownwardly-projecting innermost tubular wall D, it will form a seal, acolumn of air being conlined in the first downward passage. As thehydraulic head in pipe P is raised,the liquid will continue to overfiowthe end of pipe P; but owing to the column of air sealed within theinnermost downward passage the liquid will not fill the same, but willmount the next outer ascending passage, and the column of liquid thereinwill maintain a hydraulic head in pipe P above the end of pipe Pequivalent to the height of said column of liquid, and so on of theremaining convoluted passages. The liquid is shown in the drawing in theposition it will occupy when the joint or coupling is completed andoperating as above described.

The foregoing description of the operation applies when the two membersare put together dry, and the seal is formed as the pressure of liquidin the pipes gradually increases. If the seal is to be ready formed, asis desirable when a sealing medium of greater speciiic gravity than theliquid in the pipe is to be used or when my invention is to be used as apivot-bearing, as in Fig. 4, presently to be described, the cups of thelower member should be about half filled with the sealing liquid. Theupper member is then set into the lower member, the air being allowed toescape from the upper cups through the valves lv, which are afterwardclosed. Vhen the pressure is raised within the joint, the air in theinnermost upward passage-t'. e., between pipes P and P-will be forcedover into the first descending passage, the liquid in the firstdescending passage will be forced into the next ascending passage, andso on. It will be seen that the seal will sustain a pressure equivalentto the sum of the heads in all the ascending passages.

When the passages are filled, as first above described, by a liquid fromwithin the pipe, lthe increasing volume or capacity of the ascending anddescending passages from the center to the periphery of the nest ofcups, in case the passages are all of the same width, need not be takeninto account, for the reason that suihcient liquid will be supplied fromwithin the pipe to ll the outer upward passages of larger capacity, airbeing sealed within the successive downward passages as theabove-described operation progresses. \Vhen, however, the seal is formednot by a liquid from within the pipe, but by placing the sealing liquidin the cups of the lower member before putting the two members together,in order to derive the advantages/of my invention to the fullest extent,the successive passages from the inner to the outer ones may beprogressively narrowed a little to compensate for their increasingdiameters, thus keeping the volumes or capacities of all the passagesequal; otherwise if the passages are all of the same width and so ofprogressively-increasing volumes the displacement of a given Volume ofliquid in the innermost passage when pressure is applied will create aconstantly-decreasing hydraulic head in each successive ascending outerpassage, which, While employing the advantages of my invention in adegree,would not utilize the pressure-resisting capacities of the fullheights of the ascending passages.

My said union or joint is adapted for use as a gas, liquid, or drainpipe, and is especially useful for the latter purpose. A sanitaryfixture of this nature having a joint which is dependent upon gaskets,putty, and the like is constantly liable to leakage,\vhe1'e as myimproved joint constitutes an absolute seal for a given head of liquidin pipe P. Furthermore, it adords economy of time and labor ininstalling it over the old forms of sanitary joints, since it simplyrequires the upper member to be set into the lower member, whereupon thejoint will be complete.

Referring now to the modification of my invention, whereby it is used asa plug or cap for a pipe, as shown in Fig. 3, the foregoing descriptionis applicable in all respects, except that one of the pipes, as P,instead of serving as a pipe connection is closed, as at P4. The uppermemberA then becomes a cap or plug and the capacity of the seal toresist pressure in the pipe P depends upon the principles alreadydescribed.

Fig. 4 illustrates another modication of my invention embodied in apivot-bearing. The upper or pivot member Ax comprises the shaft Px,which is either solid or, if hollow, has a closed end and the concentriccups formed by the parts Cx and D, as heretofore described. The lower orbearing member Bx is the same as the lower member B 0f the pipe-unionabove described, except that the inner tube Py instead of being an openpipe like P' in Figs. l and 3 is closed, as at P". Cx and Cy are thecollars surrounding the parts PX and PY, respectively, and correspond tothe collars C and C in Figs. 1 and 3. The cups of the lower or bearingmember contain a liquid for the purpose of sealing the air-space withinthe cups and lubricating the members. Any liquid may be used; but thehigher the specific gravity of the liquid the greater the load which maybe borne by the upper or pivot member. The central cup of the lowermember is preferably made deeper than the rest, and the shaft Px of theupper member extends beyond the openings of its surrounding cups intothe said central cup of the lower member. So long as the load upon Px isnot sufiicient to force the liquid out of the bearing-cups the uppermember IOO IIO

will be supported on an air-cushion, whereby the friction willbe reducedto a minimum. By employing a large number' of cups and deep walls DX DYand a heavy liquid, such as mercury, t'orasealing medium excessive loadsmay be borne by the pivot member. My said pivot-joint is suitable forderricks, ordnance, and like heavy apparatus. In the same manner it willbe seen that by usi'ng a heavy sealing medium in the pipe-joint shown inFig. l or the pipe-plug shown in Fig. 3 fewer and shorter walls D and Dwill be required to maintain a given pressure of the lighter fluid inthe pipe than when the liquid contained in the pipe is to serve as asealing fluid.

- When the liquid contained in the pipe is relied upon to seal the duct,the two members of the joint may be put together dry-that is,

the cups of the lower member need contain no fluid-and the air willescape through the ends of the duct.V

\ own Wayinto the duct when the pipe is filled 4and the pressureapplied.

lto escape when the two members A and B are put together and are closedafter the union is made. v

What I claim, and desire to secure by Letters Patent, is-

l. A pipe union or plug comprising an upper member and a lower member,said members being adjacent and having an interstice between them, and aseal for said interstice comprising a duct consisting ofA a series ofascending and descending convolutions leading from said interstice,substantially as de` scribed. Y

2. A pipe union or plug comprising an upper member and a lower member,said members being adjacent and having an interstice between them, and aseal for said interstice consisting of an ascending and descending ductleading from said interstice and formed by a series or nest ofconcentric cups integral with or secured to each member, the walls ofthe cups of one member Vbeing meshed with walls of the cupsof the othermember, substantially as described.

3. A pipe union or plug comprising an upper member and a lower membersaid members being adjacent and having an interstice between them, and aseal for said interstice consisting of an ascending and descending ductleading from said interstice and formed by a series or nest ofconcentric cups integral with or secured to each member, the wallsoi:`the cups of one member being meshed with the walls of the cups of theother member,

The iiuid will then find itsand means for locking the said memberstogether,csubstantially as described.

4. A pipe union or plug comprising an upper and a lower tubular memberot different sizes,one member projecting within the other, and eachmember being provided at or near its end with a collar having series ornest of concentric walls projecting therefrom and surrounding saidtubular member, the said series of walls of one member being meshed withthe walls of the other member, substantially as described. i'

5. A pipe union or plug comprising an upper and a lower tubular memberof diiicerent sizes,one member projecting within the other, and eachmember being provided at or near its end with a collar having a seriesor nest of concentric wallsprojecting therefrom and surrounding saidtubular member, the said series of walls of one member being meshedwiththe walls of the other member, and the smaller or inner tubularmember extending beyond its surrounding nest of walls, substantially asdescribed.

6. A pipe union or plug comprising an upper and a lower tubular memberof different sizes,one member projecting within the other, and eachmember being provided at or near its end with a collar having a seriesornest of concentric walls projecting-therefrom and surrounding saidtubular member, the said series of walls of one member being meshed withthe walls of the other member, and a bayonet-'j oint or other suitablelock for securing said members together, substantially as described. Y

7. A pipe union or plug comprising an upper and a lower pipe memberhaving adjacent ends, one pipe being smaller than and proj ecting intothe other, each member being proV vided a short distance from its endwith a coll-ar from which extend in the direction of the end of thepipemember a plurality of tubular walls of different sizes and ofsubstantially equal height concentric with the pipe member, the tubularwalls of one member being meshed withthe tubular walls of th'e othermember, and the smaller inner pipe Aend extending beyond its nest orseries of walls, substantially as described.

8. A pipe union or plug comprising anupper and a lower pipe memberhaving adjacent ends, one being smaller than and projecting into theother, each member beingprovided a short distance from its end with acollar from which extend in the direction of the end of the pipe membera plurality of tubular walls'ot' different sizes and of substantiallyequal height concentric with the pipe member, the tubular walls of onemember being meshed with the tubular walls ofthe other member, and thesmaller inner pipe end eX- tending beyond'its nest or series of walls,said members being secured together by a bayonet-joint7 substantially asdescribed.

9. A pipe union or plug comprising an upper and a lower member, thelower member consisting of a pipe surrounded by a series or nest ofconcentric cups containing a sealing fluid, and the upper memberconsisting of a pipe surrounded by a series or nest of concentricinverted cups, meshed with the cups of the lower member, the upperinverted cups being provided with escapes for air, substantially asdescribed.

10. A pressure-resisting seal comprising an upper and a lower memberhaving oppositelydisposed adjacent ends, the lower member having aseries of concentric cups containing a sealing fluid and the uppermember having a series of inverted concentric cups, nieshed with thecups of the lower member, substantially as described.

ll A pressure-resisting seal comprising an upper and a lower memberhaving oppositelydisposed adjacent ends, the lower member having aseries of concentric cups containing a sealing Huid and the upper memberhaving a series of inverted concentric cups, meshed with the cups of thelower. member, said inverted cups being provided with escapes for air,substantially as described.

Signed by me at Boston, Massachusetts, this 21st day of October, 1901.

DAVID CRAIG.

Witnesses:

ROBERT CUSHMAN, FRANK S. HARTNETT.

